Grinding Element and Grinding Apparatus

ABSTRACT

A grinding element has an abrasive surface and an abutment surface which is offset by an offset from the abrasive surface. A grinding depth can be adjusted by changing the offset. The grinding element may be a grinding belt.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No. PCT/EP2017/078679, filed Nov. 9, 2017, which claims priority under 35 U.S.C. § 119 from German Patent Application No. 10 2016 222 043.8, filed Nov. 10, 2016, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a grinding element, to a grinding apparatus, and to a use of a grinding apparatus or a grinding element.

In the repair of vehicle bodywork, body parts of sheet metal have often to be cut out and removed, for example. It is necessary herein for existing spot welds or rivets to be removed, wherein spot weld cutters are used to this end, for example. It is disadvantageous that an (ideally) rectilinear accessibility has always to be provided in the use of a cutter so that the tool can be used without any slippage. It is furthermore problematic that known spot weld cutters meet their limits in the case of high-strength steels as are increasingly used in the construction of bodywork. Belt grinders or filing sanders, respectively, have proven successful when working with materials of this type. However, such belt grinders or filing sanders have the disadvantage that the truly precise removal of spot welds, rivets, etc. is not possible since no precise grinding depth is implementable when using such hand-held tools. There is consequently in particular the risk of grinding too deeply and of damaging sheet-metal panels, or sheet-metal panel portions, respectively, or components lying therebelow.

There is therefore needed a grinding element, a grinding apparatus, and a use of a grinding element which eliminate the aforementioned disadvantages and enable rapid and effective working.

According to the invention, a grinding element comprises an abrasive surface and an abutment surface, wherein the abutment surface is positioned so as to be offset from the abrasive surface by an offset, on account of which a grinding depth is adjustable, or adjusted.

This is in particular a grinding element for a grinding apparatus such as a belt grinder or a filing sander. The offset according to preferred embodiments is in a range from approximately 1 to 5 mm. The grinding apparatus expediently serves for releasing or cutting, for example, portions of (sheet-metal) body parts, wherein to this end optionally present fastening elements such as spot welds, rivets, folds, etc. have to be removed in a punctiform manner that is as accurate as possible. As has been indicated at the outset, very precise work is required herein. Multi-layer sheet-metal panels are presently increasingly installed. When grinding a spot weld on an uppermost sheet-metal layer it has to be ensured that underlying sheet-metal layers are not damaged. A precise grinding depth as a function of the respective requirement can presently be expediently adjusted by way of the offset. Moreover, belt grinders or filing sanders, respectively, offer the advantage that they can also be used in the case of high-strength steels and regions that are difficult to access. Further, said belt grinders or filing sanders, respectively, as opposed to power drills, do not require any rectilinear accessibility so that an extremely flexible use is possible.

The grinding element preferably comprises the abutment surface, or integrally configures the latter, respectively, wherein the grinding element can be a (flexible) grinding belt such as is used, for example, in the case of belt grinders or filing sanders. Alternatively, the grinding element can however also be a (rigid) grinding disk.

The grinding element is preferably configured as a grinding belt, wherein the grinding belt is configured/shaped so as to be stepped or offset, respectively, in such a manner that said grinding belt comprises or configures, respectively, both the abrasive surface as well as the abutment surface. The abrasive surface herein, when viewed along the circumferential direction, is provided so as to be centric, for example, wherein the abutment surface is formed by two lateral portions of the grinding element which are offset in a corresponding manner so as to be disposed to the left and to the right in relation to the abrasive surface. Said lateral portions advantageously have a rather smooth surface, since said lateral portions indeed likewise rotate conjointly in the circumferential direction but are not intended to assume any grinding function. The latter is solely implemented by the actual abrasive surface. According to one embodiment, a grinding element or grinding belt, respectively, of this type is configured in one part or integrally, respectively, in other words so as to be “one part” or so as to be inseparable, respectively, on account of which said grinding element or grinding belt, respectively, is advantageously replaceable as a unit. A desired grinding depth can be adjusted in an uncomplicated manner by choosing the corresponding grinding belt.

Depending on the requirement, a multi-step design embodiment which enables, for example, a correspondingly stepped contour to be shaped, or in particular to be ground, respectively, can also be chosen. A grinding element of this type, for example a grinding belt, comprises more than one abrasive surface, for example two abrasive surfaces, which are disposed in a mutually offset manner. According to one embodiment, a central, uppermost abrasive surface which is flanked by two lateral abrasive surfaces which are disposed so as to be offset to the rear is provided, when viewed along the circumferential direction, the abutment surface, or the abutment surfaces, respectively, in turn being disposed or configured, respectively, so as to be offset to said lateral abrasive surfaces.

According to one alternative embodiment, the grinding element or the grinding belt, respectively, is configured so as to be two-tiered, wherein a first tier, which configures the abrasive surface, and a second tier are in particular releasably fastened to one another. The first tier is thus preferably replaceable. To this end, corresponding form-fitting elements which enable a replacement of the first tier, for example in the case of wear or when another grinding depth is to be implemented by the use of another first tier, respectively, are expediently provided between the first and the second tier. The grinding depth can specifically be adapted in an advantageous manner by way of a different thickness of the first tier which, when required, can be replaced in an uncomplicated manner. Typical form-fitting elements are based, for example, on a hook-and-loop fastener principle, comprising corresponding hooks and eyelets, etc. Other fastening methods, for example based on adhesive means such as double-sided adhesive tapes, etc., are also possible.

According to one embodiment, the abutment surface is developed, for example by attaching a coating or a friction element, for enabling or facilitating an easy displacement on the surface to be processed, in particular when the region to be ground is not punctiform, as in the case of a rivet, but linear, as in the case of a weld seam.

The grinding element can be a grinding belt or else a grinding disk.

The invention is also directed toward a grinding apparatus comprising a grinding element according to the invention.

According to one embodiment, the grinding apparatus is a belt grinder or a filing sander, wherein the grinding element is a grinding belt which rotates along a circumferential direction. The grinding region is that region or portion at which the grinding element ultimately interacts with a workpiece or component to be processed. In the case of a filing sander this would be the front region of the tool at which the grinding belt is deflected, for example. The abutment surface, or the at least one abutment surface, respectively, is expediently provided in this region, or generally in the grinding region, respectively. The abutment surface in relation to the abrasive surface is spaced apart to the rear, so to speak, in such a manner that a predefined grinding depth is adjustable by way of said spacing. The abrasive surface can penetrate the component only until the grinding apparatus, or the grinding region, respectively, bears on the abutment surface. In the case of the belt grinder, the grinding region describes a substantially rectangular face or plane, respectively. In the case of the filing sander, the grinding region at least in portions is configured so as to be cylindrical, or has the shape of a semi-cylinder, respectively. The fundamental construction of a belt grinder or filing sander is known to a person skilled in the art and will presently not be described in more detail.

According to one embodiment, the grinding element is a grinding belt which is guided on a bearing face, wherein the bearing face forms the abutment surface. The offset, or the grinding depth, respectively, is expediently adjusted solely by way of a depth dimension or thickness, respectively, of the grinding belt. The bearing face is expediently wider than the grinding belt, or the abrasive surface, respectively, by a specific dimension and thus fulfils the function of the abutment surface. In a basic configuration this construction is similar to a grinding belt configured in steps, wherein the abutment surface formed by the bearing face however does not rotate in the case of this variant.

According to one embodiment, the abutment surface is developed for preventing any slippage of the grinding apparatus on the component to be processed. To this end, the abutment surface is provided, for example, with a type of coating, or has a specific roughness, respectively, which can facilitate the placement of the grinding apparatus on the component/workpiece.

According to one embodiment, the abutment surface is developed, for example by attaching a coating or a friction element, for enabling or facilitating an easy displacement on the surface to be processed, in particular when the region to be ground is not punctiform, as in the case of a rivet, but linear, as in the case of a weld seam.

The abutment surface can have a substantially cylindrical shape, or the shape of a semi-cylinder, respectively, so as to enable the mobility, in particular pivoting, for example, of the grinding apparatus.

The invention is also directed toward a use of a grinding apparatus according to the invention, or a grinding element according to the invention, for bodywork repair, in particular in the sector of sheet-metal processing, for example for removing spot welds or rivets.

The advantages and features mentioned in the context of the grinding apparatus apply in an analogous and corresponding manner to the grinding element as well as for the use, or vice versa and in combination with one another, respectively.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows two schematic drawings for visualizing the functional principle.

FIG. 2 is a partial view of a grinding apparatus in a perspective view.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1, viewed substantially transversely to a circumferential direction U, shows a grinding element 20 configured as a grinding belt, which has a first tier 24 and a second tier 25. An abrasive surface 22 is formed on the first tier 24. The second tier 25, by way of two corresponding lateral portions 23, forms an abutment surface 30. The abutment surface 30 is offset from the abrasive surface 22 by an offset x. Two sheet-metal layers are identified by the reference signs 81 and 82. The right half of FIG. 1 illustrates how the grinding element 20, when processing, penetrates the first sheet-metal panel 81, wherein the sheet-metal panel 82, on account of a precisely adjusted grinding depth t which corresponds to the offset x, remains entirely intact.

FIG. 2 now shows a partial view of a grinding apparatus, in particular of a filing sander, having a grinding region 2 which at least in portions is configured so as to be cylindrical. The filing sander comprises a grinding element 20 which is configured as a grinding belt and which, in the embodiment shown here, is configured so as to be two-tiered and has a first tier 24 and a second tier 25. The first tier 24 forms or comprises, respectively, an abrasive surface 22. The second tier 25 by way of two lateral portions 23 forms an abutment surface 30 which, relative to the abrasive surface 22, is offset in particular to the rear by an offset x. The grinding belt 20 rotates along a circumferential direction U and is deflected about a rotation axis D which quasi corresponds to a cylinder axis of the approximately cylindrical grinding region 2. A grinding belt 20 which is configured so as to be two-tiered, or at least so as to be stepped, respectively, such that said grinding belt 20 integrally forms the corresponding offset x by way of which a grinding depth can be adjusted has presently been described. It is indicated by way of the reference sign 4 that the component identified by said reference sign could also be a bearing face for the grinding belt 20, said bearing face being stationary. A grinding depth can thus likewise be adjusted solely by way of a depth dimension or thickness, respectively, of the grinding belt 20.

LIST OF REFERENCE SIGNS

-   2 Grinding region -   4 Bearing face -   20 Grinding element, grinding belt -   22 Abrasive surface (grinding face) -   23 Lateral portion -   24 First tier -   25 Second tier -   30 Abutment surface (abutment face) -   81 Sheet-metal panel -   82 Sheet-metal panel -   x Offset -   t Grinding depth -   U Circumferential direction -   D Rotation axis

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. A grinding element, comprising: an abrasive surface; and an abutment surface, wherein the abutment surface is positioned so as to be offset from the abrasive surface by an offset, on account of which a grinding depth is adjustable.
 2. The grinding element as claimed in claim 1, wherein the offset is in a range from approximately 1 to 5 mm.
 3. The grinding element as claimed in claim 1, wherein the grinding element is configured so as to be multi-tiered, wherein a first tier and a second tier are releasably fastened to one another.
 4. The grinding element as claimed in claim 1, wherein the abutment surface is developed for preventing any slippage of a grinding apparatus having the grinding element.
 5. The grinding element as claimed in claim 1, wherein the grinding element is a grinding belt or a grinding disk.
 6. A grinding apparatus, comprising a grinding element as claimed in claim
 1. 7. The grinding apparatus as claimed in claim 6, wherein the grinding element is a grinding belt, and a bearing face for the grinding belt forms the abutment surface.
 8. The grinding apparatus as claimed in claim 6, wherein the grinding apparatus is a filing sander.
 9. A use of a grinding apparatus comprising a grinding element, wherein the grinding element includes an abrasive surface and an abutment surface, the use comprising: positioning the abutment surface offset from the abrasive surface by an offset amount; and performing bodywork repair by grinding via the grinding apparatus, wherein a grinding depth is adjustable by changing the offset amount. 